1. Field of the Invention
The present invention relates to a method of manufacturing a tire tube and a vulcanizing apparatus therefor, and particularly to a method of manufacturing a sealant containing tire tube including an air chamber filled with air and a sealant chamber filled with a sealant, and a vulcanizing apparatus therefor.
2. Description of Related Art
FIG. 1 is a transverse sectional view of a wheel mounted with a tube having a tire including a sealant chamber. Referring to FIG. 1, a rim R of the wheel for a motorcycle is connected to a hub (not shown) via wire spokes (not shown).
A tire containing a tube T includes a tire 1 and a tube 2 contained in the tire 1 that are mounted on the rim R. The tube 2 includes a peripheral wall 4 and a partition wall 5 for partitioning the inside surrounded by the peripheral wall 4 into two parts. The peripheral wall 4 is composed of an air chamber peripheral wall 41 positioned radially inwardly of the tube 2, and a sealant chamber peripheral wall 40 positioned radially outwardly of the tube 2. The partition wall 5 is molded integrally with the peripheral wall 4.
An air chamber 3, which is surrounded by the air chamber peripheral wall 41 and the partition wall 5 in an approximately circular shape in cross-section, is filled with air. A sealant chamber 7, which is surrounded by the sealant chamber peripheral wall 40 and the partition wall 5 in an approximately arcuate shape, is filled with a known liquid sealant 8. The air chamber peripheral wall 41 has an air valve 6 for filling the air chamber 3 with air.
FIG. 4 illustrates the manufacturing steps up to and including the step of forming a tube of raw material into a tubular shape. Specifically, the above steps include a material kneading step, a tube material extrusion-molding step, a cutting step, an air valve mounting step, and a joining step.
A material composed of a crude rubber kneaded at the material kneading step is extrusion-molded into a tube material 2' by an extrusion-molding machine at the tube material extrusion-molding step. The tube material 2' is cut into a specific length during the cutting step. An air valve 6 is mounted at a suitable position on the air chamber peripheral wall 4 at the air valve mounting step. Thereafter, both ends of the tube material 2' are joined to each other at the joining step.
According to the related art method disclosed, for example, in Japanese Patent Laid-Open No. Hei 9-174710, the crude rubber, which has been formed into a tubular shape in accordance with the manner described above, is then subjected to the manufacturing steps shown as "related art steps" on the left side of FIG. 6.
At a vulcanizing die set step, as shown in FIG. 5, the annular tube material 2' is set in a vulcanizing die 18. At a first vulcanizing step, the vulcanizing die 18 is heated to vulcanize the tube material 2', thereby forming a tube 2. The tube 2 ejected from the vulcanizing die 18 at a vulcanizing die ejection step is fixed by a specialized jig (not shown) at a fixing step. At a perforating step, a sealant filling hole is opened in the sealant chamber peripheral wall 40.
Then, at a sealant filling step, the sealant chamber 7 is filled with a sealant 8 through the sealant filling hole. At a crude rubber sheet sticking step, a crude rubber sheet is stuck in such a manner so as to cover the sealant filling hole, and at a second vulcanizing step, the crude rubber sheet and its neighborhood are locally vulcanized to close the sealant filling hole, to obtain a finished tube.